<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <div class="app">
      <ul>
        <li v-for="item in list" :key="item.id">
          {{item.ha}}
          <button @click="fn1(item.id)">删除</button>
        </li>
        <button @click="fn">生成</button>
      </ul>
    </div>
    <script src="./vue.js"></script>
    <script>
      const app = new Vue({
        el: '.app',
        data: {
          list: [
            { id: 1, ha: parseInt(Math.random() * 21) },
            { id: 2, ha: parseInt(Math.random() * 21) },
            { id: 3, ha: parseInt(Math.random() * 21) },
            { id: 4, ha: parseInt(Math.random() * 21) },
            { id: 5, ha: parseInt(Math.random() * 21) }
          ]
        },
        methods: {
          fn() {
            this.list.unshift({
              id: +new Date(),
              ha: parseInt(Math.random() * 21)
            })
          },
          fn1(id) {
            this.list = this.list.filter(item => item.id !== id)
          }
        }
      })
    </script>
  </body>
</html>
